Coupling for tubes



Patented June 14, 1949 COUPLING FOR TUBES John N. Wolfram, Cleveland, Ohio, assignor to The Parker Appliance Company, Cleveland, Ohio, a corporation of Ohio Application June so, 1944, Serial no. 542,856

1 Claim. (01.285 87) The invention relates to new and useful imhereinafter referred to more in detail, the seat provements in a coupling for tubes and more particularly for a tube which is flareless.

An object of the invention is to provide a coupling of the above type having a holding sleeve moved into gripping contact with the tube by a nut, with a limiting stop for preventing over-tightening with a resulting excess deformation or crushing of the tube wherein the limiting stop is so constructed as to yield under heavy torque pressure to take up any looseness between the sleeve and tube upon repeated assemblies of the coupling.

A further object of the invention is to provide a coupling of the above type wherein the gripping end of the holding sleeve makes sealing contact both with the body member of the coupling and tube which is secured to the coupling.

A still further object of the invention is to provide a coupling of the above type wherein I said sleeve makes additional or secondary sealing contact with the body member. of the coupling and tube when heavy torque pressure is applied to the nut. I

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawings which show by way of illustration' .one embodiment of the invention:

Figure 1 is an enlarged sectional view longitudinally through the coupling with a tube in place ready to be secured to the coupling member.

Figure 2 is a similarview but showing the coupling closed and the tube firmly gripped and secured to the coupling.

The coupling as illustrated in the drawing includes a body member I having a bore 2 of subfor the tube may be done away with.

The body member I is provided with the threaded section 5 adapted to cooperate with the threaded section 6 of a nut 1. It will be understood that while this threaded section on the body member is arranged on the exterior surface thereof that the threaded connection between the nut and body member may be otherwise constructed, it being essential that there shall be a connection which will cause the nut to move onto the body member when it is turned. Said nut at its outer end has an inwardly extending portion 8 providing a recess 9 and a shoulder l0.

Disposed within the recess 9 of the nut is a holding sleeve II. This holding sleeve fits over the tube which is to be clamped to the coupling with a loose tolerance. The tube is indicated at ii in the drawings, with the end thereof in engagement with the seat 4. The 'sleeve is provided with a projecting portion l3 at its rear end which extends outwardly beyond the nut, the nut having a sufficient opening so that it is free from contact with this projecting portion of the sleeve. This projecting portion serves to dampen vibrations in the tube. I

The sleeve is provided with a shoulder I4 which is adapted to be contacted with by the shoulder It The sleeve at its inner end is cut away so as to provide a relatively thin cylindrical portion IS. The end of the sleeve is substantially stantially the same diameter as the tube which is to be secured to the coupling. 'Said body member I is provided with a threaded section 3 adapted to be attached to any part at which the tube is to be connected. The body member I is counterbored so as to provide a seat 4 for the end of the tube. As shown in the drawings, this seat 4 is substantially at right anglesto the wall of the bore. It will be understood, however, that the seat may be otherwise shaped, the essential feature being that it shall provide a means for positioning a tube in the coupling. It is also desirable when the seat is used that it shall be so constructed that it will prevent endwise movement of the tube when it is grinned and secured to the coupling. It will be understood, however. that under certain conditions 20 to the end of the body member 2| the surface is rounded. The tapered surface between the points l9 and 20 is a camming surface and also a sealing surface. This camming surface is indicated at 2L The rounded portion between the points 20 and 2| is initially spaced away from the inclined surface l8.

After the tube has been placed in the coupling and in contact with the seat 4 then the nut is threaded onto the body member. The shoulder ill of the nut contacting with the shoulder I4 of the sleeve will force the sleeve endwise on the tube. This will cause the rounded and ll of the sleeve to contact with the camming surface'il and as the sleeve is forced against this camming surface, the extreme innerfend ofthe sleeve will be contracted and will cause the sharp cutting edge 16 to cut into the tube wall rolling up a shoulder 22 in the tube l2, as shown in Figure 2. This may cause a slight inward bulging of the inner wall of the tube, but not sufficient to damage the tube or restrictthe flow passage through thetube. At the same time that the.

sharp shoulder 16 becomes embedded in the tube wall, it provides a seal between the tube and the sleeve. Likewise the contact between the rounded end ll of the sleeve and the camming surface 2|.of the body member provides: a sealing line between the sleeve and the body member. This is the main seal between the coupling and tube.

In order to prevent over-tightening of the coupling, the rounded surface on the body member i is spaced away from the inclinedsurface l8 so that these parts do not contact until the sleeve 'has been forced into firm gripping contact with the tube. As shown in Figure 2, these parts have been brought into contact and when they contact I from the spirit of'the invention as set the appended claim.

they provide a limiting stop, which will prevent over-tightening of the coupling with the resulting excess deformation or crushing of the tube.

There are, however, times when a looseness develops between the sleeve and the tube particularly when the coupling'parts are separated and reassembled. There'are other times when looseness develops due to vibratio'n of the tube or impulse forces applied to the tube.] In order to take -or crushing of the tube; it still has s ufllc 'ientyield I ing qualities to permit'the sleevebcin'g 1 forced endwise when heavytorque ressure is. applied to" take up any looseness between the sleeve and the tube which may';result upon repeated assemblies of the coupling or which may result from eXccssive vibrations of the tube afterj-it is umpedto the coupling. p I

While the body member'is shown as rounded for Contact with the inclined face It, it will be I claim:

'A coupling for tubes comprising a body mem her having a bore adapted to receive the end of a fiareless tube, a nut having threaded engagement with said body member, asleeve interposed between the nut and the body member, said body care of the situation such as just stated, the

limited stop isofa yieldable character. Ifheavy torque pressure is applied to the nut, the curved portion 20 of the body member reacting upon the inclined portion l8 of the sleeve will contact the sleeve moving it into. tighter contact with the tube andpermitting further endwise movement ofthe sleeve so as to take up this looseness which has developed. When the sleeve is further contracted, it produces a secondary or auxiliary seal between the sleeve and the tube in the region indicated at 22a. The contact between the rounded portion 20 and the inclined portion ill will provide a further secondary or auxiliary seal for the coupling.

It will be noted that the camming surface H is at a relatively small angle "to the wall of the bore, while the :rounded surface 20 is ata much larger angle. Therefore, when therounded surface 20 contacts with the inclined surface IS, the

excess torque necesary to turn the nut will warn the operator that the tube is firmly gripped and further turning of the nut would result in overtightening of the coupling. While this limiting stop insures a proper tightness of the coupling and prevents any resulting excessive deformation member being shaped within the bore to provide a cammlng surface having a gradual taper, said sleeve at the inner end thereof having a reduced portion of a substantially uniform diameter, which diameter is greater than the diameter of the inner end of the camming surface,and less than the diameter of'the outer end of the can-lming surface so that the inner end of the sleeve will be forced by the nut into engagement with the camming surface and will be contracted and caused to cut into the tube and grip the same, said I sleeverhaving an outwardly abruptly tapering surface at the outer end of the reduced portion so' that when the sleeve has been moved along the camming surface into firm grippin engagement with the tube, said abruptly tapered portion will contact with the body member at a point spaced outwardly from'sald reduced portion for limiting further endwise movement of the sleeve under normal wrench pressure.

" JOHN N. ,WOLFRAM.

, REFERENCES CITED The following references are or record in the file of this patent: V

UNITED STATES PATENT Number Name Date 1,866,914 Stover July 12, 1932 2,182,811

Kocher Dec, 12, 1939 

